Accelerator of vulcanization



Patented Feb. 17, 1931 UNITED ST TES PATENT h JAN mErrEMA; 0F AKRoN, onto, ASSIGNOR TO THE eoonYEAE TIRE & EUBBEE com- IPANY, 0E AKRON, care, A coEPo A'rIoN or 01110 a ACCELERATOR or VULGANIVZATION No Drawing.

My invention relates to the vulcanization.

of rubberfand'it has, for its primary object, the provision of desirable material for accelerating the vulcanization ofrubber products. More specifically, my invention: hasforone of its objects the provision ofan accelerator which is composed of a mercaptoxazole'or a derivative thereof. 1

mercaptans, particularly the mercaptothiazoles, have powerful'accelerating effectsupon the rate of, vulcanization "when incorporated in a rubber compound. Among the mercaptothiazoles which have been found useful for this purpose "are mercaptobenzothiazoles and various derivatives and homo logues. thereof, such as those containing chlorine andinitrogen groupssubstituted in the aryl ring. It hasalso'been observed that fpowerful accelerators areobtained by sub porated into rubber compounds'-to *produce powerful accelerators.

compounds which may be so employed are the reaction products of mercaptobenzoxaf zole and diphenylguanidine.

a One method which may be employed in preparingthis product is described as'followsh -7 i Dissolve 15.1 i grams of imercaptobenzoxaw zole in about 50 cc. of hot-alcohol and to this solution add 21 gramsofdiphenylguanidine a, Application ie'ao bber 17,

found to be a good accelerator.

I have made the discovery that, the mercaptoxazoles which are quite similar in struc ture to themercaptothiazoles, except for the replacement of the sulphurof the thiazole ring by an oxygen atom,- may also be incor- The derivatives of the benzoxazoles and the amines are particu- V larly valuable for this purpose. Among the 1927. Serial no; 226,814. l

tals separate out, which arethen filtered and dried. It is found that these crystals have a definite melting point'of about 169 or 170 mercaptobenzoxazole and diphenylguani- V dine.

The chemical reactionof these materials {maybe-represented by the following struc- Recently it has been observed that certain 1 tural equation:

"There'a'ctionproduct of mercaptonaph toxazole and diphenylguanidine has also been The mercaptonaphtoxazole may be. prepared by the following method:

,B-naphthol is treated with nitrous acid to form a nitroso derivative. i This substance is then treated with sodium'hydrosulphide (and carbon bisulphide, and mercaptonaph toxazole is produced. The reactions taking place may lee-represented according to the following chemical formula: V r "1 No similarftothat described in connection with the process for preparing the reaction prodguanidine'.

a duct of mercaptobenz oxazole and diphenyldissolved in 50 cc. of alcohol. When this mix a Y ture is allowed to coolfor' a short time, crys T I The' reaction produets oi mercaptobencaptonaphtoxazole to produce very eflicient accelerators. The first mentioned material 18 an Oll and the latter 1s a crystalline substance having a melting point ranging from 125 C. to 127 C.

The accelerators may be incorporated in rubber compounds composed of various ingredients 111 varying proportions. The fol lowlng is an example of a formula which 111- sures excellent results:

Iarts Pale crepe rubber acetone extracted 100 Zinc oxlde 5 Sulphur 3 Stearlc acld 1.5 Accelerator (mercaptoxazole or derivatlve) to 1 The appended table contains the data obtamed by testing a number of samples contaming var1ous oxazoles and derlvatlves thereof as accelerators.

llt fot/iulu s Time Percent TOIlSllB in mmelongautcs Strength tion Cure at 4 (1) Mercaptobenzoxazole 30 5.5 9 33 990 used 1% 10 2G 81 960 (2) Mercaptobenzoxazolc 30 36 157 215 755 diphenylguanidine 60 36 155 225 765 of compound used r. 90 22 127 225 795 3) lvlercapfon'iphtomzole 3O 18 54 110 820 X 00 22 160 no 1% 90 24 74 150 820 (4) Mcrcaptonaphtorazole 15 23 87 144 790 di henylguanidinc V29}, 30 34 138. 195 760 of crude compound used 45 40 163 210 745 Cure at I Mercantonaphtoxazole di- 20 ethyla1nine'( 30 21 135 765 Mcrcaptonaphtoxazole diethylamine so as 154 204 750 Mercaptobenzoxazole diethylarnine .r 20 21 70 140 825 Care at 4 l\4[ercaptonaphtoxazolc d1- ethv1aminc(%%) r. 30 19 G0 140 S55 Mcrcaptonaphtoxnzole diethylaminc 50 2O 73 155 835 Mcrcaptobenzoxazole diethylamine 70 23 8d 150 800 My invention is not limited to the specific products prevlously mentioned, but also includes the reaction products of the mercaptoxazoles and various other amines, such as butylamine, and benzylamine, all of which react with the mercaptan group of the oxazole ring to form addition products.

Although I have disclosed but the preferred embodiments of my invention and described those embodiments 1n detail, .it will be apparent to those skilled 1n the art that it is not zoXazole and mercaptonaphtoxazole with various amines other than diphenylguanidine may be prepared by the methods just discussed. For example, diethylamine reacts with both mercapt-obenzoxazole and merso limited but that various minor modifications and changes may be made therein without departing from the spirit of my invention or from the scope of the appended claims.

What I claim is:

1. A method of Vulcanizing rubber which comprises heating a mixture containing rubber, sulfur and the reaction product of mercaptobenzoxazole and a basic amine capable of reacting therewith, said product being an accelerator of vulcanization.

2. A method of vulcanizing rubber which comprises heating a mixture containing rubber, sulfur and the reaction product of mercaptobenzox'azole and a basic secondary amine, said product being an accelerator of vulcanization.

A method of vulcanizing rubber which comprises heating a mixture containing rubber, sulfur and the reaction product of mercaptobenzoxazole and a basic aromatic amine, said product being an accelerator of vulcanization. V

4. A method of vulcanizing rubber which comprises heating a mixture containing rubber, sulfur and the reaction product of mercaptobenzoxazole and diphenylguanidine.

5.. A method of accelerating the vulcanization of rubber which comprises incorporating therein a material having the following formula:

in which R is an aryl radical selected from a the presence of a material having the following formula:

o-s-R,

in which R is a basic amine residue.

8. A method of accelerating the rate of vulcanization of rubber which comprises heating it in the presence of a material having the following formula:

in which R is the residue of a basic secondar amine.

9. A method of accelerating the rate of vulcanization of rubber which comprises 5 heating it in the presence of a material hav ing the following formula: V

O: mfsqz, o

in which R is a dibenzene substituted gua11idine.

In Witness whereof, I have hereunto signed my name.

7 15 Signed at Akron, in the county of Summit,

and7State of Ohio, this 12th day of October, 192 I JAN TEPPEMA. 

